In a business (a field of product) where demand varies drastically and customer needs are diversified, there is a make-to-order strategy which starts manufacturing after receipt of an order, as a countermeasure for reducing a risk of surplus inventory and occurrence of opportunity loss. However, in the case where a lead time for manufacturing a product is long, a start of production after receipt of an order may fail in meeting a deadline required by a customer. Considering the situation above, a measure as the following is generally taken; a delivery lead time permissible by the customer is figured out, a process range is assumed as a make-to-order process, the range allowing delivery within the delivery lead time even though manufacturing is started after receiving the order, and as for the process prior thereto, make-to-stock production is performed in advance.
Since it is typically conceivable that a manufacturing lead time and a customer-allowable lead time vary among products, a selection of the make-to-order process also vary among products.
In this regard, the patent document 1 provides a technique, for example, for obtaining from locations where inventory is maintainable, one point (a decoupling point) where a requested lead time and a supply lead time are balanced with respect to each product, between a site of material and a customer. A downstream process from the decoupling point is assumed as a process for manufacturing in response to receipt of an order.